Here's my very low-tech phytoplankton culture experiment. Started with 1/2 cup of phyto water (not very densely populated) from LFS. Added to 1/2 gallon fresh SW @ 1.019(ish)SG. Add in a 15W T-8 Coralife 50/50 bulb, timered to burn 16 hours on and 8 off. Tiny air pump to rigid tubing to keep the water moving. We'll see how things turn out, if it works in a week or so I should have 1/2 gallon of very green water, which I'll split in half and start again.
Total costs:
1/2g rubbermaid container - $2 (wallyworld)
1/2cup phyto populated water - $5
here's a shot of it today after 24 hours, already starting to turn a bit green.